stats pack ?/interpretation
Date: 20 Jan 2004 13:06:28 -0800
Message-ID: <8a41a7df.0401201306.65ccffb5_at_posting.google.com>
I have a question about stats pack? I have some db files in the report that are showing over 20ms read times. In the statspack documentaion it says that if there are any read times over 20ms for a datafile something needs to be done about it. However, this database is on a SAN and I was wondering that the reason some of these datafiles might have high read times, because those particular datafiles are not in the SANS cache at the time of the request. Here is an example. Tablespace Filename
Av Av Av Av Buffer
Av Buf
Reads Reads/s Rd(ms) Blks/Rd Writes Writes/s Waits
Wt(ms)
-------------- ------- ------ ------- ------------ -------- ----------
D_CN_OMF /dev/rprod_0016_126
1,009 0 141.3 1.0 285 0 0
This file has only been read 1009 times, so I was thinking that it has high read times because it gets aged out of the SAN's cache. We are seeing high I/O wait, about an average of 30% during busy times, and hardly any CPU usage itself. We have multiple files that have these high read times. I'm just trying to get some opinions here of other sites that run on a SAN. We are running oracle 8.1.7.4 IBM SAN, AIX 5L maintenance release3 on a p690 regatta. There are currently 7 cpus and 8 gig of ram allocated to the node. If you people want, I can show more of the statspack report. The only performance problems that I see here are these high average read times.
Mike Received on Tue Jan 20 2004 - 22:06:28 CET